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From David Jencks <david_jen...@yahoo.com>
Subject Re: Lock-free HashMap
Date Thu, 17 May 2007 22:50:52 GMT

On May 17, 2007, at 3:41 PM, Marc Prud'hommeaux wrote:

>
> I recall Patrick was looking into replacing some of our slower Map  
> plumbing recently. If he is still working on that, it would be  
> interesting to see if these could be dropped in to see what the  
> performance differences were.

 From the presentation I believe it really helps to have a 400+ core  
machine and lotsa threads to see the performance differences, which  
are then rather dramatic :-).  Also the current implementation uses  
some com.sun classes (unsafe??) for CAS instructions and I got the  
impression that it uses slightly more memory than ConcurrentHashMap.

Looking forward to the results :-)

thanks
david jencks

>
>
>
>
> On May 16, 2007, at 9:21 PM, Craig L Russell wrote:
>
>> Don't know if anyone caught Cliff's preso at Java One...
>>
>> Anyone want to take a look at the new HashMap?
>>
>> Craig
>>
>> Begin forwarded message:
>>
>>> From: Kin-man Chung
>>> Date: May 15, 2007 11:24:38 AM PDT
>>> Subject: Lock-free HashMap
>>>
>>> Cliff Click talked about his lock-free HashMap at JavaOne, and
>>> demonstrated its superior scalability over ConcurrentHashMap.
>>> The source is available at
>>>
>>>   http://sourceforge.net/projects/high-scale-lib
>>>
>>> We should check this out and see if it can be used in Glassfish to
>>> boost the spec numbers.
>>>
>>>   -Kin-man
>>>
>>
>> Craig Russell
>> Architect, Sun Java Enterprise System http://java.sun.com/products/ 
>> jdo
>> 408 276-5638 mailto:Craig.Russell@sun.com
>> P.S. A good JDO? O, Gasp!
>>
>


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